Sensor signal processor apparatus

ABSTRACT

A sensor signal processor apparatus having good characteristics and providing an easy and simple interface for various sensors. The sensor signal processor apparatus includes a current source, a sensor, a ramp integrator, a comparator, and a controller. The current source generates a constant current according to a preset value, and the sensor outputs a sensor voltage using the current from the current source. The ramp integrator generates and outputs an integral voltage according to an input command, and the comparator compares the sensor voltage of the sensor with the integral voltage of the ramp integrator and outputting a result of the comparison. The controller controls the generating and outputting of the integral voltage of the ramp integrator according to the comparison result of the comparator.

TECHNICAL FIELD

The present disclosure relates to a sensor signal processor apparatus,and more particularly to, a sensor signal processor apparatus providingan easy and simple interface for various sensors and having goodperformance.

This work was supported by the IT R&D program of MIC/IITA[2006-S-041-01, Development of a common security core module forsupporting secure and trusted service in the next generation mobileterminals]

BACKGROUND ART

Recently, methods of collecting information about variations ofenvironmental conditions and operating a system according to thecollected information are increasingly required. For this, varioussensors are used to measure variations of environmental conditions, andsensor signal processor apparatuses are used to provide interfacesbetween the sensors and application systems for using measured values ofthe sensors in the application systems.

For example, values measured by various sensors such as a temperaturesensor, a humidity sensor, and a velocity sensor are processed by asensor signal processor apparatus, such that such sensors can be used asa thermometer, a hygrometer, and a velocity meter.

However, conventional sensor signal processor apparatuses have a complexcircuit structure and poor performance.

DISCLOSURE OF INVENTION Technical Problem

An aspect of the present invention provides a sensor signal processorapparatus providing an easy and simple interface for various sensors.

An aspect of the present invention also provides a sensor signalprocessor apparatus that can process measured values of a sensor morerapidly and efficiently.

An aspect of the present invention also provides a sensor signalprocessor apparatus can be applied to various application modules inconnection with various sensors.

Technical Solution

According to an aspect of the present invention, there is provided asensor signal processor apparatus including: a current source generatinga constant current according to a preset value; a sensor outputting asensor voltage using the current from the current source; a rampintegrator generating and outputting an integral voltage according to aninput command; a comparator comparing the sensor voltage output from thesensor with the integral voltage output from the ramp integrator andoutputting a result of the comparison; and a controller controlling thegenerating and outputting of the integral voltage of the ramp integratoraccording to the comparison result of the comparator.

According to another aspect of the present invention, there is provideda sensor signal processor apparatus including: a sensor including asensor resistor; a ramp integrator including a current source generatinga constant current according to a resistance of the sensor resistor, theramp integrator generating and outputting an integral voltage based onthe current generated by the current source in response to an inputcommand; a digital comparator performing an comparison operation on theintegral voltage output from the ramp integrator and outputting a resultof the comparison; and a controller controlling the generating andoutputting of the integral voltage of the ramp integrator according tothe comparison result of the digital comparator.

According to another aspect of the present invention, there is provideda sensor signal processor apparatus including: a ramp integratorgenerating and outputting an integral voltage for a sensor; a pluralityof comparators comparing the integral voltage of the ramp integratorwith arbitrary input voltages; and a controller controlling thegenerating and outputting of the integral voltage of the ramp integratoraccording to outputs of the comparators.

According to another aspect of the present invention, there is provideda sensor signal processor apparatus including: a ramp integratorincluding a current source generating a constant current, a capacitivesensor receiving the current generated from the current source forcharging, and a switch used to charge and discharge the capacitivesensor; a digital comparator performing an comparison operation on anintegral voltage output from the ramp integrator and outputting a resultof the comparison; and a controller controlling generating andoutputting of the integral voltage of the ramp integrator according tothe comparison result of the digital comparator.

Advantageous Effects

According to the present invention, the interface circuit of the sensorsignal processor apparatus can be used for various sensors. Furthermore,the interface circuit of the sensor signal processor apparatus is simpleand has good characteristics. In addition, the interface circuit of thesensor signal processor apparatus can be used for various sensors such acapacitive sensor and a resistance sensor without modification or withless modification.

Moreover, the sensor signal processor apparatus of the present inventioncan be easily adapted for a measuring system and an information securitysystem. Furthermore, the sensor signal processor apparatus has goodperformance and suitable for being manufactured in the form of asemiconductor chip.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a sensor signal processorapparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a modification version of thesensor signal processor apparatus of FIG. 1 having a multiple structure.

FIGS. 3 and 4 are circuit diagrams illustrating exemplary circuitstructures of the sensor signal processor apparatuses of FIGS. 1 and 2,respectively.

FIG. 5 illustrates an exemplary structure of a controller of FIG. 4.

FIG. 6 illustrates wave forms of signals that are output from elementsof the sensor signal processor apparatus of FIG. 4 according toEquations.

FIG. 7 is a block diagram illustrating a sensor signal processorapparatus for processing a signal of a resistance sensor according to asecond embodiment of the present invention.

FIG. 8 is a block diagram illustrating a modification version of thesensor signal processor apparatus of FIG. 7 having a multiple structure.

FIG. 9 is a circuit diagram illustrating an exemplary circuit structureof the sensor signal processor apparatus of FIG. 7.

FIG. 10 is circuit diagram illustrating an exemplary circuit structureof a sensor signal processor apparatus having two interfaces as comparedwith the circuit structure having an interface.

FIG. 11 illustrates an exemplary structure of controller of FIG. 10.

FIG. 12 illustrates wave forms of signals output from elements of thesensor signal processor apparatus of FIG. 10.

FIG. 13 is a block diagram illustrating a sensor signal processorapparatus for a capacitive sensor according to a third embodiment of thepresent invention.

FIG. 14 is a block diagram illustrating a modification version of thesensor signal processor apparatus of FIG. 13 having a multiplestructure.

FIG. 15 is a circuit diagram illustrating an exemplary circuit structureof the sensor signal processor apparatus of FIG. 13.

FIG. 16 is circuit diagram illustrating an exemplary circuit structureof a sensor signal processor apparatus having two interfaces as comparedwith the circuit structure of FIG. 15 having an interface.

FIG. 17 illustrates an exemplary circuit of the sensor signal processorapparatus of FIG. 7B for generating an internal voltage.

FIG. 18 illustrates wave forms of signals that are output from elementsof the sensor signal processor apparatus of FIG. 16.

FIG. 19 is a block diagram illustrating a sensor signal processorapparatus for a capacitive sensor according to a fourth embodiment ofthe present invention.

FIG. 20 is a block diagram illustrating a modification version of thesensor signal processor apparatus of FIG. 19 having a multiplestructure.

FIG. 21 is a circuit diagram illustrating an exemplary circuit structureof the sensor signal processor apparatus of FIG. 19.

FIG. 22 is circuit diagram illustrating an exemplary circuit structurefor a sensor signal processor apparatus having two interfaces ascompared with the circuit structure of FIG. 21 having an interface.

FIG. 23 illustrates a single supply power comparator of a sensor signalprocessor apparatus according to an embodiment of the present invention.

FIG. 24 illustrates an application example of the comparator of FIG. 23using a single supply power source having two current sources.

FIG. 25 illustrates an exemplary circuit structure of a comparator usinga single supply power source having four current sources.

FIG. 26 illustrates an application example of the comparator of FIG. 25.

FIGS. 27 and 28 illustrate an exemplary structure of a digitalcomparator according to an embodiment of the present invention.

FIG. 29 illustrates an application system and a sensor signal processorapparatus that are connected to each other according to an embodiment ofthe present invention.

FIG. 30 illustrates application examples of sensor signal processorapparatuses to various chips according to embodiments of the presentinvention.

FIG. 31 illustrates a relationship between a terminal and an informationsecurity chip including a sensor signal processor apparatus according toan embodiment of the present invention.

FIG. 32 is a view for explaining a method of authenticating aninformation security chip without association with a terminal accordingto an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Exemplary embodiments of the present invention will now be described indetail with reference to the accompanying drawings. In every possiblecase, like reference numerals are used for referring to the same orsimilar elements in the description and drawings. In the followingdescription, well-known functions or constructions are not described indetail since they would obscure the invention in unnecessary detail.

The present invention provides a sensor signal processor apparatusproviding an easy and simple interface for various sensors. Theinterface circuit of the sensor signal processor apparatus can be usedfor various sensors such a capacitive sensor and a resistance sensorwithout modification or with less modification. The sensor signalprocessor apparatus can be used in various application fields inassociation with a control unit. For example, the sensor signalprocessor apparatus of the present invention can be used in aninformation security chip for the purpose of physical security bypreventing hacking. That is, the sensor signal processor apparatus canbe used in an information security chip to process a sensor signal fordetermining whether the information security chip is physically hackedand controlling the operation of the information security chip when itis determined that the chip is hacked.

FIG. 1 is a block diagram illustrating a sensor signal processorapparatus according to a first embodiment of the present invention.

Referring to FIG. 1, the sensor signal processor apparatus includes acurrent source 110, a resistance sensor 120, a ramp integrator 130, acomparator 140, and a controller 150.

The current source 110 generates and outputs a current according to apreset value. The resistance sensor 120 produces a sensor voltageV_(RS1) using the current generated by the current source 110. The rampintegrator 130 generates an integral voltage V_(SC) according to thecontrol of the controller 150. Here, the ramp integrator 130 hastime-continuity characteristics.

The comparator 140 compares the sensor voltage V_(RS1) of the resistancesensor 120 with the integral voltage V_(SC) generated by the rampintegrator 130 and outputs a resulting voltage V_(C1).

The controller 150 outputs a control voltage V_(EN) using the resultingvoltage V_(C1) to control the integral voltage V_(SC) of the rampintegrator 130. The controller 150 can be configured in various mannersaccording to application systems. For example, the controller 150 can beconfigured with an N-bit counter and a clock. Alternatively, thecontroller 150 can be configured with a plurality of gate logics.

According to the embodiment of FIG. 1, the circuitry of the sensorsignal processor apparatus including the resistance sensor 120 can beeasily and simply constructed, and variations of properties such asvelocity, temperature, pressure, and humidity can be measured by theresistance sensor 120 in the form of resistance.

The sensor signal processor apparatus can be used in various applicationfields for various devices such as a display, a thermometer, ahygrometer, a thermohygrost at (a temperature and humidity regulator), avelocity meter, and a chip protection device by processing valuesmeasured by the resistance sensor 120 using the controller 150. Theapplication fields of the sensor signal processor apparatus can beclassified into measuring systems and information security systems.

FIG. 2 is a block diagram illustrating a modification version of thesensor signal processor apparatus of FIG. 1 having a multiple structure.

Referring to FIG. 2, the sensor signal processor apparatus includes aplurality of current sources 111 through 115, a plurality of resistancesensors 121 through 125, a ramp integrator 130, a plurality ofcomparators 141 to 145, and a controller 150.

The sensor signal processor apparatus of FIG. 2 operates in the same wayas the sensor signal processor apparatus of FIG. 1. Since the sensorsignal processor apparatus of FIG. 2 includes the plurality ofresistance sensors 121 through 125, properties of different or same kindcan be simultaneously measured by a system using the sensor signalprocessor apparatus. For example, the resistance sensor 121 can be usedas a temperature sensor, and the resistance sensor 122 can be used as ahumidity sensor. In this way, the resistance sensors 121 to 125 can beused, and thus variations of environmental conditions can besimultaneously measured using the resistance sensors 121 to 125. Valuesmeasured using the resistance sensors 121 to 125 are processed by thecontroller 150.

FIGS. 3 and 4 are circuit diagrams illustrating exemplary circuitstructures of the sensor signal processor apparatuses of FIGS. 1 and 2,respectively.

The circuit structure of FIG. 3 for the sensor signal processorapparatus of FIG. 1 includes a current source (I_(RS)) 110, a resistancesensor (R_(S1)) 120, a ramp integrator 130, a comparator 140, and acontroller 150. The current source 110 generates a predetermined currentI_(RS). The resistance sensor 120 receives the current I_(RS) from thecurrent source 110. The ramp integrator 130 has time-continuitycharacteristics. The comparator 140 compares a sensor voltage V_(RS1) ofthe resistance sensor 120 with an integral voltage V_(SC) generated bythe ramp integrator 130. The controller 150 outputs a control voltageV_(EN) using an output voltage V_(C1) of the comparator 140 for on-offcontrolling the ramp integrator 130.

In the current embodiment, the ramp integrator 130 includes a currentsource (I_(RC)), a capacitor (C_(R)), and a switch S_(R) connected tothe capacitor in parallel. In the circuit structure of FIG. 3, twovoltages V_(RS1) and V_(SC) input to the comparator 140 can be expressedby Equation 1 below.

$\begin{matrix}{{V_{R\; S\; 1} = {I_{R\; S}R_{S\; 1}}},\mspace{14mu}{V_{S\; C} = {\frac{I_{R\; C}}{C_{R}}T_{C\; 1}}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

The comparator 140 compares the sensor voltage V_(RS1) and the integralvoltage V_(SC) and outputs a resulting voltage V_(C1), and when the twovoltages V_(RS1) and V_(SC) are of the same level, the level of theresulting voltage V changes (refer to FIG. 6). That is, the level of theresulting voltage V of the comparator 140 changes from 1 to 0 (refer toFIG. 6). In the current embodiment, the level of the resulting voltageV_(C1) of the comparator 140 changes at a time T. Referring to FIG. 6,the level of the integral voltage V_(SC) increases with time from zerolevel (when time=0) to a high level. This can be expressed by Equation 2below.

$\begin{matrix}{T_{C\; 1} = {{\frac{V_{R\; S\; 1}}{I_{R\; S}}C_{R}} = {\frac{I_{R\; S}}{I_{R\; C}}R_{S\; 1}C_{R}}}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

The sensor voltage V_(RS1) of the resistance sensor 120 can be measuredby counting the number of pulses of a clock signal of the controller 150for the time T_(C1). When the clock signal has a higher frequency, thesensor voltage V_(RS1) of the resistance sensor 120 can be measured moreprecisely.

In Equation 2, T_(C1) can be adjusted by varying I_(RS)/I_(RC), andI_(RS) and I_(RC) have the same characteristics. The current source 110may include a semiconductor device such as a metal-oxide-semiconductor(MOS) transistor and a bipolar transistor.

FIG. 4 is circuit diagram illustrating an exemplary circuit structure ofthe sensor signal processor apparatus of FIG. 2. The circuit structureof FIG. 4 provides two interfaces as compared with the circuit structureof FIG. 3 providing an interface.

The sensor signal processor apparatus of FIG. 4 provides the samefunctions as the sensor signal processor apparatus of FIG. 1. Thecircuit structure of the sensor signal processor apparatus of FIG. 4includes a first current source (I_(RS)) 111, a second current source(I_(RS)) 112, a first resistance sensor (R_(S1)) 121, a secondresistance sensor (R_(S2)) 122, a ramp integrator 130, a firstcomparator 141, a second comparator 142, and a controller 150.

In the current embodiment, more precise measuring circuit can beconstructed depending on the configuration of the controller 150. FIG. 5illustrates an exemplary structure of the controller 150. The controller150 of FIG. 5 can include a NAND gate 152 and an EX-OR gate 154. Amathematical model expressed by Equation 3 below can be obtained fromthe circuit structure of FIG. 4. Furthermore, times T_(C1) and T_(C2)where output voltages of the first and second comparators 140 change canbe expressed by Equation 3 below.

$\begin{matrix}{{{{{When}\mspace{14mu} V_{{RS}\; 1}} = {{I_{RS}R_{S\; 1}} = V_{SC}}},{T_{C\; 1} = {\frac{V_{{RS}\; 1}}{I_{RC}}C_{R}}}}{{{{When}\mspace{14mu} V_{{RS}\; 2}} = {{I_{RS}R_{S\; 2}} = V_{SC}}},{T_{C\; 2} = {\frac{V_{{RS}\; 2}}{I_{RC}}C_{R}}}}} & \left\lbrack {{Equation}\mspace{14mu} 3} \right\rbrack\end{matrix}$

In the current embodiment, output values of the first and secondresistance sensors 121 and 122 can be measured by counting the number ofpulses of a clock signal of the controller 150 for times T_(C1) andT_(C2). The controller 150 can be properly configured for an applicationsystem by using the respective times T_(C1) and T_(C2) of Equation 3.Alternatively, the controller 150 can be configured using a different ΔTbetween the times T_(C1) and T_(C2) as shown in Equation 4 in order forprecise measurement with less influence by external environment.

$\begin{matrix}\begin{matrix}{{\Delta\; T} = {T_{C\; 2} - T_{C\; 1}}} \\{= {\frac{\left( {V_{{RS}\; 2} - V_{{RS}\; 1}} \right)}{I_{RC}}C_{R}}} \\{= {\frac{I_{RS}}{I_{RC}}\left( {R_{S\; 2} - R_{S\; 1}} \right)C_{R}}}\end{matrix} & \left\lbrack {{Equation}\mspace{14mu} 4} \right\rbrack\end{matrix}$

In the current embodiment, the output values of the first and secondresistance sensors 121 and 122 can be measured by counting the number ofpulses of a clock signal of the controller 150 for time ΔT. Furthermore,as shown in Equation 4, time ΔT can be adjusted by varyingI_(RS)/I_(RC), and environmental factors decreasing the performance ofthe sensor signal processor apparatus due to a sensor resistancedifference can be removed. FIG. 6 illustrates wave forms of signals thatare output from the elements of the sensor signal processor apparatus ofFIG. 4 according to above-described Equations. In FIG. 6, “switch on”and “switch off” denote turning on and off of the switch S_(R) of theramp integrator 130 in response to the control signal V_(EN) of thecontroller 150.

FIG. 7 is a block diagram illustrating a sensor signal processorapparatus for processing a signal of a resistance sensor according to asecond embodiment of the present invention.

Referring to FIG. 7, the sensor signal processor apparatus includes aresistance sensor 220, a ramp integrator 230 including a current sourcegenerating a constant current according to a sensor resistance of theresistance sensor 220, a digital comparator 240 comparing a voltageV_(CS1) from the ramp integrator 230 with a reference voltage, and acontroller 250 receives an output signal V_(C1) of the digitalcomparator 240 to generate a control signal V_(EN) for controlling theramp integrator 230. The digital comparator 240 includes a digitalSchmitt trigger.

FIG. 8 is a block diagram illustrating a modification version of thesensor signal processor apparatus of FIG. 7 having a multiple structure.

Referring to FIG. 8, the sensor signal processor apparatus includes aplurality of resistance sensors 221 through 225, a plurality of rampintegrators 231 through 235 each having a current source, a plurality ofdigital comparators 241 through 245, and a controller 250.

The sensor signal processor apparatus of FIG. 8 operates in the same wayas the sensor signal processor apparatus of FIG. 7. Since the sensorsignal processor apparatus of FIG. 8 includes the plurality ofresistance sensors 221 through 225, different properties can besimultaneously measured by a system using the sensor signal processorapparatus.

FIG. 9 is a circuit diagram illustrating an exemplary circuit structureof the sensor signal processor apparatus of FIG. 7.

The circuit structure of FIG. 9 for the sensor signal processorapparatus is configured using a ramp integrator 230 and a digitalSchmitt trigger as a digital comparator 240 to provide interfacing.

The sensor signal processor apparatus includes a resistance sensor 220,a ramp integrator 230 having a current sensor, a digital comparator 240comparing a voltage V_(SC) of the ramp integrator 230 with apredetermined reference voltage, and a controller 250.

The ramp integrator 230 includes a current source (I_(RS 1)) generatinga predetermined current according to the resistance R_(S1) of theresistance sensor 220, a capacitor (C_(R)) receiving the current I_(RC1)of the current source I_(RS1) of the ramp integrator 230, and a switchS_(R) for charging and discharging the capacitor (C_(R)).

The characteristics of the sensor signal processor apparatus of FIG. 9can be expressed by Equation 5 below similar to Equation 1 for thesensor signal processor apparatus of FIG. 3

$\begin{matrix}{V_{{SC}\; 1} = {\frac{I_{{RS}\; 1}}{C_{R}}T_{C\; 1}}} & \left\lbrack {{Equation}\mspace{14mu} 5} \right\rbrack\end{matrix}$

The digital comparator 240 receives only one input voltage. The digitalcomparator 240 has high and low threshold voltages V_(thH) and V_(thL).The digital comparator 240 compares the voltage V_(SC) of the rampintegrator 230 with the high threshold voltage V_(thH). When the twovoltages V_(SC) and V_(thH) are of the same, an output voltage V_(C1) ofthe digital comparator 240 changes.

That is, the output voltage V_(C1) of the digital comparator 240 changesfrom 0 to 1 as shown in FIG. 12. The output voltage V_(C1) of thecomparator 240 changes at a time T_(C1). The voltage V_(SC) increaseswith time from zero level (when time=0) to a high level. This can beexpressed by Equation 6 below.

$\begin{matrix}{{T_{C\; 1} = {\frac{V_{thH}}{I_{{RS}\; 1}}C_{R}}},{V_{{CS}\; 1} = V_{thH}}} & \left. {{Equation}\mspace{14mu} 6} \right\rbrack\end{matrix}$

An output value of the resistance sensor 220 can be detected by countingthe number of pulses of a clock signal of the controller 250 for thetime T_(C1). When the clock signal has a higher frequency, output valuesof the resistance sensor 220 can be measured more precisely.Furthermore, since the sensor signal processor apparatus of FIG. 9includes the digital comparator 240, an additional comparison voltagesource (refer to V_(RS1) of FIG. 1) is not necessary.

FIG. 10 is circuit diagram illustrating an exemplary circuit structureof the sensor signal processor apparatus of FIG. 8. The circuitstructure of FIG. 10 provides two interfaces as compared with thecircuit structure of FIG. 9 providing an interface.

Referring to FIG. 10, the circuit structure of the sensor signalprocessor apparatus includes two resistance sensors 221 and 222, tworamp integrators 231 and 232 each having a current source, two digitalcomparator 242 and 242, and a controller 250.

FIG. 11 illustrates an exemplary structure of the controller 250.

Referring to FIG. 11, the controller 250 can include an AND gate 252 andan EX-OR gate 254. A mathematical model expressed by Equation 7 belowcan be obtained from the circuit structure of FIG. 10. Times T_(C1) andT_(C2) where output voltages of digital comparators 241 and 242 changecan be calculated using Equation 7.

$\begin{matrix}{{{{{When}\mspace{14mu} V_{thH}} = V_{{SC}\; 1}},{T_{C\; 1} = {\frac{V_{{SC}\; 1}}{I_{{RS}\; 1}}C_{R}}}}{{{{When}\mspace{14mu} V_{thH}} = V_{{SC}\; 2}},{T_{C\; 2} = {\frac{V_{{SC}\; 2}}{I_{{RC}\; 2}}C_{R}}}}} & \left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack\end{matrix}$

In the current embodiment, output values of the resistance sensors 221and 222 can be measured by counting the number of pulses of a clocksignal of the controller 250 for times T_(C1) and T_(C2), respectively.The controller 250 can be properly configured for an application systemby using the respective times T_(C1) and T_(C2) of Equation 7.Alternatively, the controller 250 can be configured using a different ΔTbetween the times T_(C1) and T_(C2) as shown in Equation 8 in order forprecise measurement with less influence by external environment.

$\begin{matrix}\begin{matrix}{{\Delta\; T} = {T_{C\; 2} - T_{C\; 1}}} \\{= {\left( {\frac{1}{I_{{RS}\; 2}} - \frac{1}{I_{{RS}\; 1}}} \right)C_{R}V_{thH}}} \\{= {\left( {\frac{1}{{aR}_{S\; 2}} - \frac{1}{{aR}_{S\; 1}}} \right)C_{R}V_{thH}}}\end{matrix} & \left\lbrack {{Equation}\mspace{14mu} 8} \right\rbrack\end{matrix}$

where is a nonlinear environment coefficient (e.g., a nonlineartemperature coefficient).

In the current embodiment, the output values of the resistance sensors221 and 222 can be measured by counting the number of pulses of a clocksignal of the controller 250 for ΔT. Environmental factors decreasingthe performance of the sensor signal processor apparatus due to a sensorresistance difference can be removed. FIG. 12 illustrates wave forms ofsignals output from the elements of the sensor signal processorapparatus of FIG. 10 according to the above-described mathematicalmodels (Equations).

FIG. 13 is a block diagram illustrating a sensor signal processorapparatus for a capacitive sensor according to a third embodiment of thepresent invention.

Referring to FIG. 13, the sensor signal processor apparatus includes aramp integrator 330, a comparator 340, and a controller 350.

The ramp integrator 330 includes a current source (I_(CS)) (refer toFIG. 15) generating a constant current, a capacitor (C_(S1)) (refer toFIG. 15) receiving the current I_(CS) of the current source, and aswitch S_(R) for charging and discharging the capacitor (C_(SS)).

The comparator 340 compares two voltages. For example, the comparator340 compares a voltage generated by the ramp integrator 330 with anexternal voltage or an internal voltage.

The controller 350 can be configured in various manners. For example,the controller 350 can be configured with an N-bit counter and a clockaccording to application systems. Alternatively, the controller 350 canbe simply configured with several gate logics.

According to the current embodiment, when variations of sensingproperties such as velocity, temperature, pressure, and humidity aremeasured using a capacitive sensor, the circuitry of the sensor signalprocessor apparatus can be easily and simply constructed for thecapacitive sensor. Furthermore, the sensor signal processor apparatus inwhich values measured by a capacitive sensor are detected by thecontroller 350 can be used in various application fields for variousdevices such as a display, a thermometer, a hygrometer, a pressure gage,a thermohygrost at (a temperature and humidity regulator), a velocitymeter, and a chip protection device. The application fields of thesensor signal processor apparatus can be broadly classified intomeasuring systems and information security systems.

FIG. 14 is a block diagram illustrating a modification version of thesensor signal processor apparatus of FIG. 13 having a multiplestructure.

Referring to FIG. 14, the sensor signal processor apparatus includes aplurality of ramp integrators 331 through 335, a plurality ofcomparators 341 through 345, and a controller 350. The comparators 341through 345 compare an internal or external voltage V_(SR) with voltagesV_(CS1) through V_(CSn) received from the ramp integrators 331 through335.

Therefore, a system including the sensor signal processor apparatus cansimultaneously measure various properties using various kinds ofresistance sensors. For example, a system including the sensor signalprocessor apparatus can simultaneously measure properties such astemperature and humidity using resistance sensors such as a temperaturesensor and a humidity sensor. Values measured in this way are processedby the controller 350.

FIG. 15 is a circuit diagram illustrating an exemplary circuit structureof the sensor signal processor apparatus of FIG. 13.

The circuit structure of FIG. 15 for the sensor signal processorapparatus includes a ramp integrator 330, a comparator 340, and acontroller 350. The ramp integrator 330 includes a current source(I_(CS)) generating a constant current, a capacitor (C_(S1)) (acapacitive sensor) receiving the current I_(CS) generated by the currentsource, and a switch S_(R) for charging and discharging the capacitor(C_(S1)). The comparator 340 compares a voltage V_(CS1) generated by theramp integrator 330 with an external or internal voltage V_(SR). Thecontroller 350 receives an output signal of the comparator 340 andgenerates a control signal V_(EN) for controlling the ramp integrator330.

The current embodiment is characterized in that an interface forprocessing a sensor signal is constructed using the ramp integrator 330.

The sensor signal processor apparatus having above-describedcharacteristics can be expressed by Equation 9 below.

$\begin{matrix}{V_{{SC}\; 1} = {\frac{I_{CS}}{C_{S\; 1}}T_{C\; 1}}} & \left\lbrack {{Equation}\mspace{14mu} 9} \right\rbrack\end{matrix}$

If the ramp integrator 330 generates an internal voltage V_(SR) using acurrent source and a resistor for improving circuit characteristics, theinternal voltage V_(SR) can be expressed by Equation 10 below.V _(SR) =I _(SR) R _(S)  [Equation 10]

An exemplary circuit structure of the ramp integrator 330 for this caseis illustrated in FIG. 17.

The comparator 340 compares the two voltages V_(CS1) and V_(SR), and thevoltage level of an output signal of the comparator 140 changes when thetwo voltages V_(CS1) and V_(SR) are of the same level (refer to FIG.18). Here, the voltage level of the output signal of the comparator 340changes from 1 to 0. That is, the level of the voltage V_(CS1) increaseswith time from zero level (when time=0) to a high level. This can beexpressed by Equation 11 below.

$\begin{matrix}{T_{C\; 1} = {{\frac{V_{SR}}{I_{CS}}C_{S\; 1}} = {\frac{I_{SR}}{I_{CS}}R_{s}C_{S\; 1}}}} & \left\lbrack {{Equation}\mspace{14mu} 11} \right\rbrack\end{matrix}$

Output values of a resistance sensor can be detected by counting thenumber of pulses of a clock signal of the controller 350 for the timeT_(C1). Referring to Equation 11, the time T_(C1) can be adjusted byvarying I_(SR)/I_(CS), and I_(RS) and I_(RC) have the samecharacteristics. The current source (I_(CS)) may include a semiconductordevice such as a MOS transistor and a bipolar transistor.

FIG. 16 is circuit diagram illustrating an exemplary circuit structurefor the sensor signal processor apparatus of FIG. 14. The circuitstructure of FIG. 16 provides two interfaces as compared with thecircuit structure of FIG. 15 providing an interface.

Referring to FIG. 16, the sensor signal processor apparatus includesramp integrators 331 and 332, comparators 341 and 342, and a controller350 that have the same structures as those of the elements of the sensorsignal processor apparatus of FIG. 15.

The operation of the sensor signal processor apparatus of FIG. 16 can beexpressed by the same mathematical model as that for the operation ofthe sensor signal processor apparatus of FIG. 15. However, the sensorsignal processor apparatus of FIG. 16 can be more precise according tothe configuration of the controller 350. For this, the controller 350can include a NAND gate and an EX-OR gate like the controller 150 ofFIG. 5. In this case, a mathematical operation model of the sensorsignal processor apparatus can be expressed with respect to times T_(C1)and T_(C2) where output voltages of the comparators 341 and 342 change,as shown by Equation 12 below.

$\begin{matrix}{{T_{C\; 1} = {\frac{V_{{CS}\; 1}}{I_{CS}}C_{S\; 1}}},{T_{C\; 2} = {\frac{V_{{CS}\; 2}}{I_{CS}}C_{S\; 2}}}} & \left\lbrack {{Equation}\mspace{14mu} 12} \right\rbrack\end{matrix}$

Although the controller 350 can be configured for an application systemby using the respective times T_(C1) and T_(C2) of Equation 12, thecontroller 350 is configured using a different ??T between the timesT_(C1) and T_(C2) shown in Equation 13 in order for precise measurementwith less influence by unstable external environment factors.

$\begin{matrix}\begin{matrix}{{\Delta\; T} = {T_{C\; 2} - T_{C\; 1}}} \\{= {\frac{V_{SR}}{I_{RC}}\left( {C_{S\; 2} - C_{S\; 1}} \right)}} \\{= {\frac{I_{SR}}{I_{CS}}\left( {C_{S\; 2} - C_{S\; 1}} \right)R_{S}}}\end{matrix} & \left\lbrack {{Equation}\mspace{14mu} 13} \right\rbrack\end{matrix}$

In the current embodiment, output values of resistance sensors can bemeasured by counting the number of pulses of a clock signal of thecontroller 350 for time ΔT. Furthermore, as shown in Equation 13, timeΔT can be adjusted by varying and environmental factors decreasing theperformance of the sensor signal processor apparatus due to a sensorresistance difference can be removed. FIG. 18 illustrates wave forms ofsignals that are output from the elements of the sensor signal processorapparatus of FIG. 16 according to Equation 13.

FIG. 19 is a block diagram illustrating a sensor signal processorapparatus for a capacitive sensor according to a fourth embodiment ofthe present invention.

Referring to FIG. 19, the sensor signal processor apparatus includes aramp integrator 430, a digital comparator 440, and a controller 450.

The ramp integrator 430 includes a current source generating apredetermined current, a capacitor receiving a current from the currentsource, and a switch for charging and discharging the capacitor.

The digital comparator 440 compares a voltage output from the rampintegrator 430 with a predetermined reference voltage. The digitalcomparator 440 includes a digital Schmitt trigger.

The controller 450 generates a control signal V_(EN) according to anoutput signal of the digital comparator 440 to control the rampintegrator 430.

FIG. 20 is a block diagram illustrating a modification version of thesensor signal processor apparatus of FIG. 19 having a multiplestructure.

The sensor signal processor apparatus of FIG. 20 has the sameoperational characteristics as the sensor signal processor apparatus ofFIG. 19. However, the sensor signal processor apparatus of FIG. 20 canbe used in a system that measures a plurality of propertiessimultaneously using various capacitive sensors.

Referring to FIG. 20, the sensor signal processor apparatus includes aplurality of ramp integrators 431 through 435, a plurality of digitalcomparators 441 through 445, and a controller 450. The comparators 441through 445 compare an internal or external voltage V_(SR) with voltagesV_(CS1) through V_(CSn) received from the ramp integrators 431 through435.

FIG. 21 is a circuit diagram illustrating an exemplary circuit structureof the sensor signal processor apparatus of FIG. 19.

In the current embodiment, the sensor signal processor apparatus (aninterface for processing a sensor signal) is constructed using a rampintegrator 430 and a digital comparator 440.

The circuit structure of FIG. 21 for the sensor signal processorapparatus includes the ramp integrator 430, the digital comparator 440,and a controller 450. The ramp integrator 430 includes a current source(I_(CS)) generating a constant current, a capacitive sensor (C_(S1))receiving a current I_(CS) from the current source, and a switch S_(R)for charging and discharging the capacitive sensor (C_(S1)). The digitalcomparator 440 compares a voltage V_(SC) of the ramp integrator 430 witha predetermined voltage. The controller 450 receives an output signalV_(C1) of the digital comparator 440 and generates a control signalV_(EN) for on-off controlling the ramp integrator 430.

The circuit structure of FIG. 21 can be expressed by Equation 14 that isequal to Equation 9 for the circuit structure of FIG. 15. However, thedigital comparator 440 uses two threshold voltages V_(thH) and V_(thL),and thus the output signal V_(C1) of the digital comparator 430 variesin association with the threshold voltages V_(thH) and V_(thL).

$\begin{matrix}{V_{{SC}\; 1} = {\frac{I_{CS}}{C_{S\; 1}}T_{C\; 1}}} & \left\lbrack {{Equation}\mspace{14mu} 14} \right\rbrack\end{matrix}$

In detail, the digital comparator 440 has a high threshold voltageV_(thH) and a low threshold voltage V_(thL). The digital comparator 440compares the voltage V_(SC1) of the ramp integrator 430 with the highthreshold voltage V_(thH).

The voltage level of an output signal V_(C1) of the comparator 440changes when the two voltages V_(thH) and V_(SC1) are of the same level.That is, the voltage level of the output signal V_(C1) of the comparator440 changes from 1 to 0. The voltage level of the output signal V_(C1)of the comparator 440 changes at a time T_(C1). That is, the level ofthe voltage V_(SC1) increases with time from zero level (when time=0) toa high level. This can be expressed by Equation 15 below.

$\begin{matrix}{{T_{C\; 1} = {\frac{V_{thH}}{I_{CS}}C_{S\; 1}}},{V_{{CS}\; 1} = V_{thH}}} & \left\lbrack {{Equation}\mspace{14mu} 15} \right\rbrack\end{matrix}$

Output values of the capacitive sensor can be detected by counting thenumber of pulses of a clock signal of the controller 450 for the timeT_(C1). Detection precision can be increased by using a clock signalhaving a high frequency. Furthermore, an additional power source for areference voltage is not necessary since the digital comparator 440 isused.

FIG. 22 is circuit diagram illustrating an exemplary circuit structurefor the sensor signal processor apparatus of FIG. 20. The circuitstructure of FIG. 22 provides two interfaces as compared with thecircuit structure of FIG. 21 providing an interface.

Referring to FIG. 22, the sensor signal processor apparatus includesramp integrators 431 and 432, digital comparators 441 and 442, and acontroller 450 that have the same structures as those of the elements ofthe sensor signal processor apparatus of FIG. 21.

The operation of the sensor signal processor apparatus of FIG. 22 can beexpressed by the same mathematical model as that for the operation ofthe sensor signal processor apparatus of FIG. 21. However, the sensorsignal processor apparatus of FIG. 22 can be more precise according tothe configuration of the controller 450. For this, the controller 450can include an AND gate and an EX-OR gate like the controller 250 ofFIG. 11. In this case, a mathematical operation model of the sensorsignal processor apparatus can be expressed with respect to times T_(C1)and T_(C2) where output voltages of the comparators 441 and 442 change,as shown by Equation 16 below.

$\begin{matrix}{{{{{When}\mspace{14mu} V_{thH}} = V_{{CS}\; 1}},{T_{C\; 1} = {\frac{V_{{CS}\; 1}}{I_{CS}}C_{{CS}\; 1}}}}{{{{When}\mspace{14mu} V_{thH}} = V_{{CS}\; 2}},{T_{C\; 2} = {\frac{V_{{CS}\; 2}}{I_{CS}}C_{{CS}\; 2}}}}} & \left\lbrack {{Equation}\mspace{14mu} 16} \right\rbrack\end{matrix}$

In the current embodiment, output values of resistance sensors can bemeasured by counting the number of pulses of a clock signal of thecontroller 450 for times T_(C1) and T_(C2), respectively. The controller450 can be properly configured for an application system by using therespective times T_(C1) and T_(C2) of Equation 16. Alternatively, thecontroller 450 can be configured using a different ΔT between the timesT_(C1) and T_(C2) as shown in Equation 17 below in order for precisemeasurement with less influence by external environment.

$\begin{matrix}\begin{matrix}{{\Delta\; T} = {T_{C\; 2} - T_{C\; 1}}} \\{= {\left( \frac{C_{{CS}\; 2} - C_{{CS}\; 1}}{I_{CS}} \right)V_{thH}}}\end{matrix} & \left\lbrack {{Equation}\mspace{14mu} 17} \right\rbrack\end{matrix}$

In the current embodiment, the output values of the resistance sensorscan be measured by counting the number of pulses of a clock signal ofthe controller 450 for time ΔT. Environmental factors decreasing theperformance of the sensor signal processor apparatus due to a sensorresistance difference can be removed. Signals that are output from theelements of the sensor signal processor apparatus of FIG. 22 accordingto Equations 16 have wave forms as illustrated in FIG. 18. However, thewave forms of output voltages V_(C1) and V_(C2) of the digitalcomparator 441 and 442 are inversed.

A comparator is necessary for the sensor signal processor apparatus ofthe present invention. Various comparators can be used according thecircuit structure of the sensor signal processor apparatus. For example,in terms of supply power, comparators that can be used for the sensorsignal processor apparatus of the present invention can be classifiedinto comparators receiving positive and negative supply voltages andcomparators receiving one of positive and negative supply voltages.Furthermore, according to application systems using the sensor signalprocessor apparatus, a comparator requiring two power sources or acomparator requiring a single power source can be used.

FIG. 23 illustrates a comparator 140 of a sensor signal processorapparatus according to an embodiment of the present invention. Thecomparator 140 uses a single supply power source. The comparator 140 canuse two supply power sources by applying both positive and negativevoltages with respect to the ground.

The comparator 140 can be widely used for processing a sensor signalusing a single supply power source. The comparator 140 has a simplecircuit structure, and it is easy to construct the comparator 140 usinga semiconductor device. Particularly, the comparator 140 ischaracterized in that an input signal is biased using a p-channel metaloxide semiconductor (PMOS) device. Referring to FIG. 23, MOS devices M1to M5 operate as a differential amplifier, and MOS devices M6 and M7operate as a common-source amplifier. PMOS devices Mp1 and Mp2 andcurrent sources (I_(S)) operate as a bias circuit. When input signalsV_(IN1+) and V_(IN1−) are biased using the PMOS devices and the currentsources, the comparator 140 can be mathematically modeled as shown byEquation 18 below.

$\begin{matrix}{{V_{{{IN}\; 1} +} = {{V_{{IN} +} + V_{{SG}\; 1}} = {V_{{IN} +} + \left( \sqrt{\frac{I_{D}}{K_{P}} + V_{t}} \right)}}}{V_{{{IN}\; 1} -} = {{V_{{IN} -} + V_{{SG}\; 2}} = {V_{{IN} -} + \left( \sqrt{\frac{I_{D}}{K_{P}} + V_{t}} \right)}}}} & \left\lbrack {{Equation}\mspace{14mu} 18} \right\rbrack\end{matrix}$

The biased input signals V_(IN1+) and V_(IN1−) are input to thedifferential amplifier and the common-source amplifier and are output asshown in Equation 19 below.V _(IN+) >V _(IN−) ,V _(IN1+>) V _(IN1−) ,V _(out) =V _(dd)V _(IN+) >V _(IN−) ,V _(IN1+) >V _(IN1−) ,V _(out)=0  [Equation 19]

The comparator 140 is characterized by high impedance at an inputterminal and a simple circuit structure. In addition, the comparator 140can be easily constructed using a semiconductor device such as a MOSdevice and a bipolar device.

FIG. 23 illustrates a comparator 140 of a sensor signal processorapparatus according to an embodiment of the present invention. Thecomparator 140 uses a single supply power source. The comparator 140 canuse two supply power sources by applying both positive and negativevoltages with respect to the ground.

FIG. 24 illustrates an application example of the comparator 140 of FIG.23 using a single supply power source having two current sources.

FIG. 25 illustrates an exemplary circuit structure of a comparator usinga single supply power source having four current sources, and FIG. 26illustrates an application example of the comparator of FIG. 25.

The comparator of FIG. 25 has the same mathematical model as that of theFIG. 23. However, the comparator of FIG. 25 is configured without aresistor.

FIGS. 27 and 28 illustrate an exemplary structure of the digitalcomparator 440 according to an embodiment of the present invention.

The digital comparator 440 receives a single input signal and outputs asingle output signal. The digital comparator 440 uses a high thresholdvoltage and a low threshold voltage. FIGS. 27 and 28 illustrate anexemplary digital comparator that can be used in the sensor signalprocessor apparatus of the present invention. In the case of using thedigital comparator 440 in the sensor signal processor apparatus of thepresent invention, an additional power source is not necessary since thedigital comparator 440 can perform a comparing operation on a singleinput signal, as compared with the case of using a comparator requiringtwo input signals for performing a comparing operation.

FIG. 29 illustrates an application system 180 and a sensor signalprocessor apparatus 100 that are connected to each other according to anembodiment of the present invention.

Referring to FIG. 29, the sensor signal processor apparatus 100 includesa sensor 120, an interface 170, and a controller 150. The sensor signalprocessor apparatus 100 is connected to the application system 180 toprovide a processed sensor signal to the application system 180.

Application systems such as a measuring system and an informationsecurity system can be constructed more easily and simply by using thesensor signal processor apparatus of the present invention. For example,when the application system 180 is a display device requiring atemperature measurement mechanism, the application system 180 can beeasily provided with the temperature measurement mechanism byconstructing the sensor signal processor apparatus 100 to process anoutput signal of a temperature sensor. When the application system 180is a security chip, the sensor signal processor apparatus 100 can beconstructed to provide information protection functions to theapplication system 180.

FIG. 30 illustrates application examples of sensor signal processorapparatuses to various chips according to embodiments of the presentinvention.

Referring to FIG. 30( a), a controller 150, an interface 170, and asensor 120 of a sensor signal processor apparatus are embedded in a chip1100. Referring to FIG. 30(b), a controller 150 and an interface 170 ofa sensor signal processor apparatus are embedded in a chip 1100, and asensor 120 of the sensor signal processor apparatus is separated fromthe chip 1200.

Referring to FIG. 30( c), a controller 150, interfaces 171 and 175, andsensors 121 and 125 of a sensor signal processor apparatus are embeddedin a chip 1300.

Referring to FIG. 30( d), a controller 150 and interfaces 171 and 175 ofa sensor signal processor apparatus are embedded in a chip 1400, andsensors 121 and 125 of the sensor signal processor apparatus areseparated from the chip 1400.

FIG. 31 illustrates a relationship between a terminal 1800 and aninformation security chip 100 including a sensor signal processorapparatus according to an embodiment of the present invention.

The information security chip 100 is embedded in the terminal 1800 forthe purpose of security.

Referring to FIG. 31, the information security chip 100 can be embeddedin the terminal 1800 for the purpose of security through the followingprocedures: a sensor security device is embedded in the terminal 1800during a manufacturing process (S100); and the terminal 1800 isauthenticated in response to a user's request (S200).

In detail, the terminal 1800 requests initial value setting (S110).Then, a manufacturer embeds the information security chip 100 into theterminal 1800 and sets a sensor using an initial value, and theinformation security chip 100 measures the set initial value and storesthe measured initial value (S120).

The measured initial value is transmitted to the terminal 1800 (S130).Then, the terminal 1800 performs initial value setting using thereceived initial value (S140).

Thereafter, the terminal 1800 is sold to a user. To safely use theterminal 1800, the user requests security authentication (S210). Then,the information security chip 100 embedded in the terminal 1800 comparesthe initial value (Si) of the sensor with an authentication sensor value(SA) (S220). The information security chip 100 analyzes a chip stateusing the comparison result and informs the terminal 1800 of theanalysis result (s230). Then, the terminal 1800 determines whether it isauthenticated or not by using the comparison result and reports thedetermination result to the user (S240).

FIG. 32 is a view for explaining a method of authenticating aninformation security chip 100 without association with a terminalaccording to an embodiment of the present invention.

The information security chip 100 can be embedded in a smart card forphysical safety.

First, the information security chip 100 is manufactured by embedding asensor security device into the information security chip 100 (S300).For this, a user measures and stores an initial value of a sensor(S310).

Next, the sensor security device authenticates the information securitychip 100 in response to a user's request (S400).

For this, the sensor security device compares an initial value (Si) ofthe sensor with an authentication sensor value (SA) (S410) anddetermines from the comparison result whether the information securitychip 100 is hacked (S420).

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

1. A sensor signal processor apparatus comprising: a current sourcegenerating a constant current according to a preset value; a sensoroutputting a sensor voltage using the current from the current source; aramp integrator generating and outputting an integral voltage accordingto an input command; a comparator comparing the sensor voltage outputfrom the sensor with the integral voltage output from the rampintegrator and outputting a result of the comparison; and a controllercontrolling the generating and outputting of the integral voltage of theramp integrator according to the comparison result of the comparator. 2.The sensor signal processor apparatus of claim 1, further comprising atleast one current source, at least one sensor, and at least onecomparator.
 3. The sensor signal processor apparatus of claim 1, whereinthe sensor is one of a resistance sensor, a capacitive sensor, and aninductance sensor that are capable of collecting different information.4. The sensor signal processor apparatus of claim 1, wherein the rampintegrator comprises a capacitor and a switch that are connected inparallel, and the integral voltage is generated by charging thecapacitor using the current generated by the current source.
 5. Thesensor signal processor apparatus of claim 4, wherein the controllercomprises: an EX-OR gate generating a pulse signal in response to anoutput signal of the comparator; and a NAND gate controlling a switch ofthe ramp integrator connected to a capacitor of the ramp integrator inparallel.
 6. The sensor signal processor apparatus of claim 1, whereinthe comparator comprises two p-channel metal oxide semiconductor (PMOS)transistors or two PNP transistors for biasing an input signal voltageusing a power source having two current sources.
 7. The sensor signalprocessor apparatus of claim 1, wherein the controller is formed into asemiconductor chip.
 8. A sensor signal processor apparatus comprising: asensor including a sensor resistor; a ramp integrator including acurrent source generating a constant current according to a resistanceof the sensor resistor, the ramp integrator generating and outputting anintegral voltage based on the current generated by the current source inresponse to an input command; a digital comparator performing ancomparison operation on the integral voltage output from the rampintegrator and outputting a result of the comparison; and a controllercontrolling the generating and outputting of the integral voltage of theramp integrator according to the comparison result of the digitalcomparator.
 9. The sensor signal processor apparatus of claim 8, furthercomprising at least one sensor, at least one ramp integrator, and atleast one digital comparator.
 10. The sensor signal processor apparatusof claim 8, wherein the sensor is one of a resistance sensor, acapacitive sensor, and an inductance sensor that are capable ofcollecting different information.
 11. The sensor signal processorapparatus of claim 8, wherein the digital comparator comprises an analogor digital Schmitt trigger.
 12. The sensor signal processor apparatus ofclaim 8, wherein the ramp integrator comprises a capacitor and a switchthat are connected in parallel, and the integral voltage is generated bycharging the capacitor using the current generated by the currentsource.
 13. The sensor signal processor apparatus of claim 12, whereinthe controller comprises: an EX-OR gate generating a pulse signal inresponse to an output signal of the comparator; and an AND gatecontrolling a switch of the ramp integrator connected to a capacitor ofthe ramp integrator in parallel.
 14. A sensor signal processor apparatuscomprising: a ramp integrator generating and outputting an integralvoltage for a sensor; a plurality of comparators comparing the integralvoltage of the ramp integrator with arbitrary input voltages; and acontroller controlling the generating and outputting of the integralvoltage of the ramp integrator according to outputs of the comparators.15. The sensor signal processor apparatus of claim 14, wherein the rampintegrator comprises: a current source generating a constant current; acapacitor receiving the current generated from the current source forcharging; and a switch used to charge and discharge the capacitor. 16.The sensor signal processor apparatus of claim 14, further comprising atleast one ramp integrator.
 17. The sensor signal processor apparatus ofclaim 14, wherein the arbitrary input voltages to the plurality ofcomparators are common voltages having the same potential level.
 18. Thesensor signal processor apparatus of claim 14, wherein the rampintegrator comprises a capacitor and a switch that are connected inparallel, and the integral voltage is generated by charging thecapacitor using the current generated by the current source.
 19. Thesensor signal processor apparatus of claim 18, wherein the controllercomprises: an EX-OR gate generating a pulse signal in response to anoutput signal of the comparator; and a NAND gate controlling a switch ofthe ramp integrator connected to a capacitor of the ramp integrator inparallel.
 20. A sensor signal processor apparatus comprising: a rampintegrator including a current source generating a constant current, acapacitive sensor receiving the current generated from the currentsource for charging, and a switch used to charge and discharge thecapacitive sensor; a digital comparator performing an comparisonoperation on an integral voltage output from the ramp integrator andoutputting a result of the comparison; and a controller controllinggenerating and outputting of the integral voltage of the ramp integratoraccording to the comparison result of the digital comparator.
 21. Thesensor signal processor apparatus of claim 20, wherein the digitalcomparator comprises an analog or digital Schmitt trigger.
 22. Thesensor signal processor apparatus of claim 20, further comprising atleast one ramp integrator and at least one digital comparator.
 23. Thesensor signal processor apparatus of claim 20, wherein the rampintegrator comprises a capacitor and a switch that are connected inparallel, and the integral voltage is generated by charging thecapacitor using the current generated by the current source.
 24. Thesensor signal processor apparatus of claim 23, wherein the controllercomprises: an EX-OR gate generating a pulse signal in response to anoutput signal of the comparator; and an AND gate controlling a switch ofthe ramp integrator connected to a capacitor of the ramp integrator inparallel.